The invention relates to a surgical instrument, in particular for endoscopy, having closable jaws comprising jaw parts such as forceps or scissor limbs which are fixed on a pull element, at least one jaw part forming an axis of rotation with the pull element and being arranged rotatably about this axis of rotation and the pull element passing at least partially through a shank tube.
Surgical instruments of this kind are known in the form of forceps, scissors, clamps or the like in numerous embodiments and are used for a very wide variety of purposes. In general, they comprise two jaw parts which are moved relative to one another, clamping, cutting or shearing then being effected.
Reference is made purely by way of example to German Offenlegungsschrift 3,921,935, which discloses endoscopy forceps. Here, the forceps limbs are connected to one another via a pivot pin. Coupled to the forceps limbs on the other side of this pivot pin is a pull cable, a pull rod or the like. Connected to the pull cable is a guiding element which has at least one guiding channel in which there engages a lever extension which is formed on a forceps limb on the far side of the pivot pin or of a pivot. If a pull is exerted on this guiding element, the jaws formed by the forceps limbs close or open.
A particular disadvantage of these hitherto known forceps is the fact that they can be disassembled, cleaned and sterilized after use only with considerable trouble. Assembly in turn also requires a large amount of time and is associated with touching the parts, which are per se to be kept sterile.
In addition, in the case of many surgical instruments of this kind, the mechanism leaves much to be desired, especially as regards the transmission of force to the jaw parts.
German Utility Models 87 12 328.2 and 88 14 560.3 furthermore disclose endoscopy forceps in which the jaw parts form an axis of rotation with the pull element. These jaw parts are guided in corresponding wall openings in the shank tube, but this is very imprecise. The transmission of force for opening and closing the jaws also leaves much to be desired. In addition, the upper sleeve has to be unscrewed from the spiral for the purpose of cleaning.
The underlying object of the present invention is to provide as perfect a mechanism as possible in combination with optimum transmission of force to the jaw parts, with disassembly of the surgical instrument at the same time being extremely easy and taking little time.